Butcher's Nails: The Horus Heresy Series

The primarch Angron: gladiator-king and Horus' lunatic attack dog. Never having hidden his resentment for his brothers, he now carves a bloody swathe through the galaxy in the Warmaster's name, with the Heresy providing a convenient excuse to indulge his love of brutal warfare. When they are tasked with a secretive mission alongside the Word Bearers Legion, the World Eaters' violent tendencies soon attract the attention of xenos raiders, troubled by the portents surrounding the primarch's berserk fury and his ultimate destiny as 'the Blood God's son'....